4 files changed, 99 insertions, 2 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs b/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs
index 5ebeace..2ac68e3 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs
@@ -87,6 +87,7 @@ public static class BSParam
     public static bool ShouldUseHullsForPhysicalObjects { get; private set; }   // 'true' if should create hulls for physical objects
     public static bool ShouldRemoveZeroWidthTriangles { get; private set; }
     public static bool ShouldUseBulletHACD { get; set; }
+    public static bool ShouldUseSingleConvexHullForPrims { get; set; }
 
     public static float TerrainImplementation { get; private set; }
     public static int TerrainMeshMagnification { get; private set; }
@@ -342,6 +343,10 @@ public static class BSParam
             false,
             (s) => { return ShouldUseBulletHACD; },
             (s,v) => { ShouldUseBulletHACD = v; } ),
+        new ParameterDefn<bool>("ShouldUseSingleConvexHullForPrims", "If true, use a single convex hull shape for physical prims",
+            true,
+            (s) => { return ShouldUseSingleConvexHullForPrims; },
+            (s,v) => { ShouldUseSingleConvexHullForPrims = v; } ),
 
         new ParameterDefn<int>("CrossingFailuresBeforeOutOfBounds", "How forgiving we are about getting into adjactent regions",
             5,
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
index 8e05b58..a4a8794 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
@@ -316,7 +316,10 @@ public sealed class BSScene : PhysicsScene, IPhysicsParameters
                 break;
             case "bulletxna":
                 ret = new BSAPIXNA(engineName, this);
+                // Disable some features that are not implemented in BulletXNA
+                m_log.InfoFormat("{0} Disabling some physics features not implemented by BulletXNA", LogHeader);
                 BSParam.ShouldUseBulletHACD = false;
+                BSParam.ShouldUseSingleConvexHullForPrims = false;
                 break;
         }
 
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
index 809435d..794857c 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
@@ -226,8 +226,23 @@ public sealed class BSShapeCollection : IDisposable
         //     made. Native shapes work in either case.
         if (prim.IsPhysical && BSParam.ShouldUseHullsForPhysicalObjects)
         {
-            // Update prim.BSShape to reference a hull of this shape.
-            BSShape potentialHull = BSShapeHull.GetReference(m_physicsScene, false /*forceRebuild*/, prim);
+            // Use a simple, single mesh convex hull shape if the object is simple enough
+            BSShape potentialHull = null;
+
+            PrimitiveBaseShape pbs = prim.BaseShape;
+            if (BSParam.ShouldUseSingleConvexHullForPrims
+                && pbs != null
+                && !pbs.SculptEntry
+                && PrimHasNoCuts(pbs)
+                )
+            {
+                potentialHull = BSShapeConvexHull.GetReference(m_physicsScene, false /* forceRebuild */, prim);
+            }
+            else
+            {
+                potentialHull = BSShapeHull.GetReference(m_physicsScene, false /*forceRebuild*/, prim);
+            }
+
             // If the current shape is not what is on the prim at the moment, time to change.
             if (!prim.PhysShape.HasPhysicalShape
                         || potentialHull.ShapeType != prim.PhysShape.ShapeType
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSShapes.cs b/OpenSim/Region/Physics/BulletSPlugin/BSShapes.cs
index 3346626..9ef2923 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSShapes.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSShapes.cs
@@ -832,6 +832,80 @@ public class BSShapeCompound : BSShape
 }
 
 // ============================================================================================================
+public class BSShapeConvexHull : BSShape
+{
+    private static string LogHeader = "[BULLETSIM SHAPE CONVEX HULL]";
+    public static Dictionary<System.UInt64, BSShapeConvexHull> ConvexHulls = new Dictionary<System.UInt64, BSShapeConvexHull>();
+
+    public BSShapeConvexHull(BulletShape pShape) : base(pShape)
+    {
+    }
+    public static BSShape GetReference(BSScene physicsScene, bool forceRebuild, BSPhysObject prim)
+    {
+        float lod;
+        System.UInt64 newMeshKey = BSShape.ComputeShapeKey(prim.Size, prim.BaseShape, out lod);
+
+        physicsScene.DetailLog("{0},BSShapeMesh,getReference,newKey={1},size={2},lod={3}",
+                                prim.LocalID, newMeshKey.ToString("X"), prim.Size, lod);
+
+        BSShapeConvexHull retConvexHull = null;
+        lock (ConvexHulls)
+        {
+            if (ConvexHulls.TryGetValue(newMeshKey, out retConvexHull))
+            {
+                // The mesh has already been created. Return a new reference to same.
+                retConvexHull.IncrementReference();
+            }
+            else
+            {
+                retConvexHull = new BSShapeConvexHull(new BulletShape());
+                BulletShape convexShape = null;
+
+                // Get a handle to a mesh to build the hull from
+                BSShape baseMesh = BSShapeMesh.GetReference(physicsScene, false /* forceRebuild */, prim);
+                if (baseMesh.physShapeInfo.isNativeShape)
+                {
+                    // We get here if the mesh was not creatable. Could be waiting for an asset from the disk.
+                    // In the short term, we return the native shape and a later ForceBodyShapeRebuild should
+                    //     get back to this code with a buildable mesh.
+                    // TODO: not sure the temp native shape is freed when the mesh is rebuilt. When does this get freed?
+                    convexShape = baseMesh.physShapeInfo;
+                }
+                else
+                {
+                    convexShape = physicsScene.PE.BuildConvexHullShapeFromMesh(physicsScene.World, baseMesh.physShapeInfo);
+                    convexShape.shapeKey = newMeshKey;
+                    ConvexHulls.Add(convexShape.shapeKey, retConvexHull);
+                }
+
+                // Done with the base mesh
+                baseMesh.Dereference(physicsScene);
+
+                retConvexHull.physShapeInfo = convexShape;
+            }
+        }
+        return retConvexHull;
+    }
+    public override BSShape GetReference(BSScene physicsScene, BSPhysObject prim)
+    {
+        // Calling this reference means we want another handle to an existing shape
+        //     (usually linksets) so return this copy.
+        IncrementReference();
+        return this;
+    }
+    // Dereferencing a compound shape releases the hold on all the child shapes.
+    public override void Dereference(BSScene physicsScene)
+    {
+        lock (ConvexHulls)
+        {
+            this.DecrementReference();
+            physicsScene.DetailLog("{0},BSShapeConvexHull.Dereference,shape={1}", BSScene.DetailLogZero, this);
+            // TODO: schedule aging and destruction of unused meshes.
+        }
+    }
+}
+
+// ============================================================================================================
 public class BSShapeAvatar : BSShape
 {
     private static string LogHeader = "[BULLETSIM SHAPE AVATAR]";